I was surprised to learn that https://www.engadget.com/dropbox-records-first-profit-ever-1... it's the first year Dropbox is profitable since going public.
Regarding USBs, Dropbox's messaging at the time was "throw out your USB drives", and this was before smartphones or ubiquitous dependable network connections. At the time, if I had to give a presentation in a university classroom, Dropbox wasn't moving the bar much on that particular problem.
Is your ego really that fragile that you can't admit you made a mistake judging a business?